(1) Field of the Invention
This invention relates to an anti-twist key lock with changeable locking device, especially a key lock which having revolving front plug to prevent it from twisting or knocking by vandals or thieves to unlock or break up.
(2) Description of the Prior Art
In order to protect individual's life and property, various safety locks are used widely in our daily life. The conventional safety lock almost having a hollow lock case in which an interlock tumbler set is installed therein, the key can be inserted into the front end of the hollow lock case to actuate the interlock tumbler set, further, the rear end of the hollow lock case being covered with a back plug to locate the interlocking tumbler set, and a plurality of screws being screwed through the circumference of the hollow lock case into the back plug to fix it. However, the back plug may apart from the hollow lock case by knocking violently the front end of the key lock assembly. Accordingly, an improved key lock assembly has been developed in present, the key lock assembly having a hollow lock case, the back end of the hollow lock case being closed, the front open end of the hollow lock case being covered with a front plug. The front plug is fixed on the hollow lock case by means of a plurality of screws, further, the center of the front plug having a through hole for inserting the key into the interlocking tumbler set. Such kind of safety lock can prevent vandals or thieves from knocking the plug to unlock or break up the lock, however, the vandals or thieves can insert a tool into the through  hole of the front plug to twist violently to break the lock.